Lifting tongs



Jan. 12, 1932. A. PORTUONDO LIFTING TONGS Filed June 1, 1929 PatentedJan. 12, 1932 UNITED STATES PATENT OFFICE A'URELIO PORTU'ONDO, OFFELTON, CUBA, ASSIGNOR TO 13ETIFELEIEIEIVI STEEL COMPANY, A. CORPORATIONOF PENNSYLVANIA LIF'IING TONGS Application filed. June 1,

This invention relates to lifting tongs, and more particularly to theautomatic releasing type.

An object of my invention is to provide a tong which will securely gripan object while being lifted or lowered.

A further object is to provide a releasing device which will open thetongs and automatically lock them in that position to insure the releaseof the tongs from the object being handled.

My improved tong is particularly useful when handling explosive chargeswhich are to be lowered into a hole. When the charge has reached thebottom of the hole, the tongs are automatically released from the chargeand prevented from closing again while being withdrawn from the hole.

The novel features of my invention will be more fully understood fromthe following description and claims taken with the drawings, in whichFig. 1 is an elevation of the tongs in open and closed position. Thefull lines illustrating the relation of its parts when gripping anobject and the dotted lines illustrating the relative position of itsparts in open or released position.

Fig. 2 is a section taken on the line 22 of Fig. 1 and shows thegripping ends of the tongs in released position relative to the obj ectbeing handled.

Referring to the drawings: I have shown my device as comprising a pairof elongated lever members 10 pivotally connected near their lower endsby a rivet 11 or the like. At a point 12 slightly below the pivot, thelevers are twisted at an angle of 90 and bent outwardly as shown at 13.The lower ends of the levers 14 are made wider than the main arms 10,and curved as shown in Fig. 2. The lower ends of the curved portions 14are formed with lateral extensions 15 and comparatively sharp at theiredges which constitute gripping jaws.

The upper ends of the levers are provided with holes 16 within which areengaged the links 17 which in turn are engaged within a ring 18 which isadapted to be engaged by a lifting hook or hoisting cable, not shown.

Intermediate the pivot 11 and the ends of the tongs 15, is provided atoggle joint 19. The joint comprises two short levers 20 and 21 providedwith pivoted connections 22 at their outer ends to L shaped brackets 23which in turn are secured to the bent portions 13 of the levers 10. Theinner ends of the toggle levers are pivotally connected by a. rivetedpin 24 or other suitable means. The toggle levers are provided withprojecting faces 25 and 26 respectively, which are adapted to form jawsand to abut each other when the tongs are in an open or releasedposition. It will be noted that when the tongs are in their releasedposition, as shown by the dotted lines of Fig. 1, that the jaws 25 and26 are so positioned relative to their angular movement that the pivotedcenter 24 lies above the line 27 intersecting the centers of the pivots22, which constitutes the dead center of the joint. In other words, whenthe pivoted center of the toggle has passed over the dead center,further movement of the center joint in an upward direction is preventedby the abutting jaws 25 and 26.

It will be obvious that with the tongs suspended from a hoist line, thatthe tendency of the lower ends will be to move toward each other and tocollapse the toggle joint either upwardly or downwardly but with thetongs in their opened position and the toggle prevented from furthermovement above the dead center point, the tongs cannot move inwardlyuntil the toggle has been moved in a downward direction to break thejoint.

In the use of the tongs, if the tongs are open and the toggle is in itsuppermost or locked position, the toggle is broken by forcing itdownwardly over its dead center point. The tongs are then lowered overthe charge until the center portion 19 of the toggle rests upon thecharge. The lower ends of the tongs are then brought together intogripping relation with the charge which causes a slight backwardmovement of the tongs relative to the charge which establishes theirnormal gripping position. vVhen a pull is applied to the hoist line, theupward strain on the ring 18 will cause the links 17 and the arms 10 ofthe tongs to be brought together and consequent- 1y swing the leversabout the pivoted connection 11 so that the gripping jaws 15 willbindingly engage the charge as shown by the full lines in Fig. 1. Thecharge may then be low- 5 ered into the hole.

After the charge has reached the bottom of the hole, the hoist line isslackened which causes the gripping edges of the tongs to be releasedfrom the charge, and the tongslfy reason of their weight, slipdownwardly over the charge. It will be seen that as the tongs movedownwardly relative to the charge, and inasmuch that the center portionof the toggle is resting on the top of the charge, that the resultingaction will be to straighten out the toggle joint which causes the tongsto open, and after the center of the toggle has passed beyond the deadcenter point and the opposing jaws of the joint are brought together,

that no further opening of the tongs can take place, and by reason ofthe relative position of the pivoted points of the toggle, the tongswill be held open, thereby allowing the tongs to be lifted and the endsprevented from closing until the toggle is again broken.

It will be seen from the foregoing description and a study of thedrawings that I have provided a simply constructed and inexpensive toolwhich will be efficient and safe in use. The tongs are especiallyadapted to handle explosive charges which are to be lowered into a holeand thereafter to be automatically and positively released, without theaccompanying danger of again engaging the charge in an insecure manner,whereby the charge might again be lifted and caused to fall with apossible resulting premature explosion.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications, without departing from the spiritthereof, and I desire therefore that only such limitations shall beplaced thereupon as are imposed by the prior art, or as are specificallyset forth in the appended claims.

Having thus described my invention what I claim as new and desire tosecure by Let- 50 ters Patent is:

1. Tongs for lowering explosive charges into a deep hole, comprisingcrossed levers pivotally connected to each other, curved jaws at thelower ends of the levers, said jaws being of uniform section formed assectors of a ring of greater length than their projecting width andhaving parallel longitudinal edges, gripping means at the ends of saidjaws, a hoist line means connecting said hoist line with the upper endsof the levers for drawing them together, and means effective upon theslacking of said hoist line to automatically release the tongs when thecharge has reached the bottom of the hole.

G 2. Tongs for lowering explosive charges into a deep hole, comprisingcrossed levers pivotally connected to each other, curved jaws at thelower ends of the levers formed as sectors of a ring with gripping meansat their ends, said levers being twisted and outwardly bent at a pointbelow said pivot t form connections between the levers and the jaws,means connected with the upper ends for drawng them toget 181 and meansto automatically release the tongs from the charge and lock them inopened position when the charge has reached the bottom of the hole.

3. Tongs for lowering explosive charges into a deep hole, comprisingcrossed levers pivotally connected to each other, curved jaws at thelower ends of the levers, said jaws being formed as sectors of a ring ofgreater length than their projected width and having longitudinallystraight inner and outer faces, gripping means at the ends of said jaws,and means to automatically release and open the tongs when the chargehas reached the bottom of the hole and to hold the jaws in longitudinalparallel position when opened.

4. Tongs for lowering explosive charges into a deep hole, comprisingcrossed levers pivotally connected to each other, curved jaws at thelower ends of the levers, said jaws being formed as sectors of a ring ofgreater length than their projected width, gripping means at the ends ofsaid jaws, and means to automatically release and open the tongs whenthe charge has reached the bottom of the hole and to hold the jaws inlongitudinal parallel position when opened, the curved portion of thejaws being of substantially uniform section to a point above the articlebeing handled when in gripping position.

5. Tongs for lowering articles into a hole, comprising levers pivotallyconnected to each other, curved gripping members of substantiallyuniform section at the lower ends of the levers and of greater lengththan their width, a toggle positioned adjacent the upper ends of thegripping members, said toggle comprising links having inner ends ofgreater bearing surface than their outer ends, the inner end of one ofsaid links having a depending lip portion formed within the planes ofthe faces of said end, the other link having a projecting portion formedat right angle to its face and adapted to abut the l lip portion of itscompanion link when the tongs are in opened position, and brackets toconnect the outer ends of the links to the tong levers.

' In testimony whereof I hereunto aflix my 125 signature.

AURELIO PORTUONDO.

